When you buy a new CPU cooler, you'll find that the thermal paste is either included in the box or pre-applied on the heatsink. Likewise, your graphics card also comes with thermal paste pre-applied on the die from the factory. While that thermal paste is adequate to prevent your CPU or GPU from overheating, you could get better temperatures by spending your money on a high-quality thermal paste.

While you can find cheap thermal pastes for as low as $5 on Amazon and other major retailers, I highly recommend spending $10-20 on a premium thermal paste like the Arctic MX-6, Noctua NT-H2, or Thermal Grizzly Kryonaut Extreme. That extra $10-15 you spend would be well worth the investment in the long run for the following reasons.

4 Higher thermal conductivity

It can transfer heat more efficiently

The thermal paste acts as a conductive layer between your CPU (or GPU) and the heatsink. Without it, imperfections on the surface of the CPU or the heatsink will allow air pockets to form, which negatively impacts heat transfer because, as you may know, air is a poor conductor. However, not all thermal pastes are made equally; some are better at conducting heat than others. That's why you should always check a paste's thermal conductivity before buying it.

Thermal conductivity is measured in W/mK, and you'll find it mentioned in the thermal paste's specifications — at least if it's branded. Cheap thermal pastes have a thermal conductivity of roughly 4-5 W/mK, and while that isn't particularly bad by any means, high-quality thermal pastes today claim double this number. For example, the Arctic MX-6 has a thermal conductivity of 10.5 W/mK. The higher the thermal conductivity of a paste, the quicker it will transfer heat from your CPU or GPU to the heatsink, allowing it to run cooler.

Some liquid metal thermal compounds, like the Thermal Grizzly Conductonaut, claim a thermal conductivity of 73 W/mK. However, I wouldn't recommend using them because they're electrically conductive, and any spillage may cause short circuits and damage your motherboard.

3 Lower temperatures

Faster heat transfer means your CPU runs cooler

Since a thermal paste with a higher thermal conductivity can quickly transfer heat away from the CPU or GPU die to the heatsink, it can prevent thermal buildup and also allow the cooler to run more efficiently, resulting in lower operating temperatures. I've tried the pre-applied thermal paste on CPU coolers before, and every time I re-pasted with a high-quality thermal paste having a conductivity of around 10 W/mK, my CPU temperatures dropped by roughly 5 to 10C. You can expect better results if the thermal conductivity of your thermal paste is higher.

A high-quality thermal paste gives you more thermal headroom if you plan to overclock your CPU for better gaming performance. Additionally, since your CPU runs cooler, you can expect it to sustain higher clock speeds for much longer and avoid thermal throttling issues. And don't forget that a cooler CPU will also last longer due to reduced thermal stress on the silicon. You can also expect stable temperature readings because they have better consistency and viscosity to ensure even coverage of the CPU's IHS (Integrated Heat Spreader).

2 Lower fan speeds

Your fans won't work as hard at lower temperatures

This is an indirect benefit of using a high-quality thermal paste. You may have noticed how your CPU cooler fans ramp up when gaming, rendering, or performing any other demanding task on your PC. But that's because your CPU temperature is high under heavy load, and your cooler tries to lower it by working harder. However, if you lower your CPU temperature by 10C using a high-quality thermal paste, your fans won't need to spin fast nearly as often.

As a result, you can expect your PC to be noticeably quieter during demanding workloads. More importantly, this can extend the lifespan of your CPU cooler since the fans aren't constantly running at full speed to stop your CPU from overheating.

1 Longevity

You don't have to reapply it often

Thermal pastes don't last forever, but cheap thermal pastes tend to dry out and lose their effectiveness within a year. So, you'll have to remove the cooler and reapply the thermal paste to get optimal temperature readings again, which is a tedious task. However, a high-end thermal paste can remain effective for multiple years since it's less prone to drying out due to heat. Sure, you will notice a slight increase in CPU temperature over time, but it won't be alarming enough to warrant a reapplication.

All in all, a premium thermal paste is well worth the investment if you don't want to deal with the maintenance hassle. And since you won't have to reapply it as often, it may prove to be cost-effective in the long run. I'd rather spend $15 on the Arctic MX-6 and not worry about temperature readings for 3 to 4 years than spend $5 every year on a cheap thermal paste.

You get what you pay for

Thermal pastes are inexpensive, and that extra $10 you spend can make a big difference to your CPU temperatures and the longevity of your cooler in the long run. You could even get away with a less powerful CPU cooler as long as you use a high-end thermal paste like the Thermal Grizzly Kryonaut Extreme. So, the next time you're in the market for a new CPU cooler, make sure you buy a premium thermal paste along with it instead of using the one that comes in the box.